1. Field of Invention
The invention relates to a device and method for medical detection and, in particular, to a device and method detecting cornea through optics.
2. Related Art
A corneal measuring instrument is a kind of optical device for measuring the corneal surface, and after the profile of the corneal surface is acquired, the contact lenses can be designed to fit different users. Besides, the corneal profile also can present some ocular diseases. Hence, the corneal profile can be applied to the preoperative assessment and postoperative corneal recovery in the surgical procedure of RK, PK or LASIK. Therefore, an accurate corneal profile is very important for the following treatment.
FIG. 1 is a schematic diagram of a conventional optical image device for the corneal measuring.
The optical device 1 in FIG. 1 includes an image projector 10, a positioning light source 12, a measuring light source 14 and an image processing unit 16. The image projector 10 can provide an image for the target to be measured and the target to be measured needs to continuously see the image, so that the cornea 18 of the target can be positioned and the measurement error caused by the displacement during the measuring process can be avoided. Then, the positioning light source 12 can provide a light beam that is transmitted to the cornea 18, and the light beam is reflected to enter the receiving end of the image processing unit 16. Through the reflected light beam of the positioning light source 12, the image processing unit 16 can be adjusted into a better measuring state to increase the measurement accuracy.
In the actual measuring, the measuring light source 14 can provide a plurality of concentric-circle light beams for the cornea 18, and the profile of the surface of the cornea 18 (i.e. curvature) can be determined by the deviation situation of the reflected light beams.
However, this kind of optical device just can generate the profile of the upper corneal surface but can't measure the total thickness of the cornea accurately. In order to measure the corneal thickness, a side light source is generally added in to provide a light beam obliquely entering the cornea, and the side corneal profile can be detected by the reflection of the light beam. Nevertheless, this kind of method still can't accurately measure the real profile of the lower corneal surface.
Therefore, it is an important subject to provide an optical device and method which can measure the upper and lower corneal surfaces to provide a stereoscopic corneal image.